A number of systems and methods for actuating vehicular safety devices are well known in the art. Typically, a sensor is used to determine vehicle acceleration (and therefore deceleration). The signal is processed to determine when to activate various passive safety devices, such as inflatable restraints and safety belt pre-tensioners.
To provide optimum protection for the passengers of the vehicle, it is important to accurately and expeditiously determine the relative severity of a crash event to allow sufficient time for the deployment of an inflatable restraint. It is also important to refrain from deploying an inflatable restraint for crash events in which the restraint would not benefit the passengers. Such events may include low-velocity impacts and the like.
Most current frontal airbag deployment algorithms for discrimination of must-fire pole events from no-fire events rely on the use of jerk or length of acceleration. This dependence reduces the effectiveness of those algorithms from reliably discriminating must-fire pole events from no-fire crashes, namely, no-fire car-to-car and no-fire pole crashes. In addition, current algorithms are sensitive to high impact rough road events which result in either inadvertent deployment or longer discrimination times for high speed frontal events.